AptPkg::hash(3pm) User Contributed Perl Documentation AptPkg::hash(3pm)NAMEAptPkg::hash - a helper class for implementing tied hashes
SYNOPSIS
use AptPkg::hash;
DESCRIPTION
The AptPkg::hash class provides hash-like access for objects which have
an underlying XS implementation.
Such objects need to add AptPkg::hash to @ISA, provide get, set and
exists methods, and an iterator class.
AptPkg::hash
new([XS_OBJECT])
Create a object as a tied hash. The object is implemented as a
hash reference blessed into the class, which in turn is tied to
AptPkg::hash.
This means that both $obj->method() and $obj->{key} valid, the
latter invoking get/set (through FETCH/STORE).
The tie associates an array reference with the hash, which
initially contains a reference to the hash, the XS object and an
anon hash which may be used by subclasses to store state
information.
If no XS object is passed, one is created via new in the XS class.
The name of that class is constructed from the class name, by
lower-casing the last component and prefixing it with an underscore
(eg. AptPkg::Config becomes AptPkg::_config).
If the module contains a @KEYS array, then the private hash will be
populated with those entries as keys (see the description below of
the AptPkg::hash::method class).
_self, _xs, _priv
Accessors which may be used in subclass methods to fetch the three
array elements associated with the hash reference.
keys(ARGS)
In a scalar context, creates and returns a new iterator object (the
class name with the suffix ::Iter appended).
The XS object, the private hash and any arguments are passed to the
constructor.
In an array context, the iterator is used to generate a list of
keys which are then returned.
The iterator class must implement a next method, which returns the
current key and advances to the next.
AptPkg::hash::method
The AptPkg::hash::method class extends AptPkg::hash, providing a simple
way to map a fixed set of keys (defined by the @KEYS array) into method
calls on either the object, or the internal XS object.
Classes inheriting from AptPkg::hash::method should provide an iterator
class which inherits from AptPkg::hash::method::iter.
AUTHOR
Brendan O'Dea <bod@debian.org>
perl v5.18.1 2013-05-10 AptPkg::hash(3pm)